Rotary earth excavating machine



Sept. 24, 1957 G. E. MYAXEY ROTARY EARTH EXCAVATING MACHINE 2 Sheets-Sheet 1 Filed March 25, 1954 United Sttes Patent jO 2,807,104 ROTARY EARTH EXCAVATINGQMACHINE George E. Maxey, Seattle, Wash, assignor to Alvin F. Johanson, Seattle, Wash.

Application March 25, 1954, Serial No. 418,529

-9 Claims. '(CI. 37-96) This invention relates-to an earth excavator or digging machine and an object of this invention is to-provide an excavatingor digging machine which :issirnple in con- '-struction,'not expensive to manufacture, and highly effi- :cient in 'operation.

Another object is to provide a digging machine havcurving around'the drum and rigidly secured to thedrum and a medial portion extending approximately tangentially away from'the drum and an outer end portion 'curved in a reverse directionfrom the inner end portion and-terminating in a chisel shaped diggerpoint, whereby rotation of the drum-in the direction of curvature of the .outerend of the-springwill apply the digger pointto the work and resistance offered by the work to forward -movement of the diggerpoint will cause the spring to be wound on the drum and'the digger point tobe moved toward the-drum.

Another object is to provide a digger unit having a rotatable drum provided with an outwardly extending 'leaf spring of approximately 8 shape, said spring having on its-outer enda chisel shaped-diggerpoint which is movable in a substantially circular path and points inits -direction of movement and which, when it is applied to the ground fordigging purposes, will shave and sliceand crumble away soft materiaL-such as'clay, and will pick andjarloose by impact solidified material, suchas packed earth andgravel, and to further providev adigger unit of this type in which the leaf spring is mounted and arranged so that-if thediggerpoint on the outer endthereof encounters an obstruction, such as a boulder .too large to be readilydislodged,said spring will either drawthe digger point inwardly enabling it -to pass the obstruction or will allow saiddigger point to -be deflectedside wise around the obstruction.

Another object of this invention 'is to provide effucient elevator type material disposal means cooperatively associated with the digging means andadjustable relative thereto for elevating and disposing of earth which is loosened up and displaced by the digging means.

Other objects of the invention will be apparent from the following description taken in connection with the accompanying drawings.

In thedrawings: V I

Figure 1 is asomewhat diagrammatic view in side elevation of a digging machine constructed in accordance with this invention showing the same as it may appear when in'use.

Fig. lis'za'view partly in top plan and partly in sec- .tion of-said machine, takensubstantially on broken line 2-2 of Fig. 1, parts-being omitted.

:Fig. 3 is -a view in elevation, with parts in section, looking in .the .directionof .brokenline 33 of Fig. 1.

Fig. 4..is a detached side view, on a larger scale than Figs. 1, 2 and 3, showing a rotatable drum having leaf spring members of approximately 8 shape attachedthereto, said springmembers carrying digger points, one of said spring members being broken away and arretracted position of the other spring member being shownby :dot

an auxiliary or extension drum which may be secured thereto.

Fig. 7 is a fragmentary sectional view illustrating a preferred manner of using a wedge between a drum andia spring member'to impart an outward incline to the spring member.

Like reference numerals designate like parts throughout the 'several views.

The digging mechanism embodied in this invention comprises an upright frame or housing of hollow rectangular shape in .cross sectionwhich is herein shown to be made up .of two'upper side plates :10 and :11 and :two lower side plates 12 and 13 and spacer members 14. The spacer members '14 are disposed between the marginal portions ofthe side plates 10, 11, 12 and 13 and all of saidiframe members '10 to 14 inclusive arefixedly secured together to form. a strong and rigid frame struc- :ture'inwhich the two side plates 10 and 12 aresupported :parallel to andin spaced apart relation from the other two side plates 11 and 13. The two upper side plates 10 and 11 may be welded tothe spacer members 14-. 'The two lowerside plates 12 and 13 are preferablysecured to the spacer members 14 bycap screws or bolts .15. This makes it possible to readily attach and detach the two lower side plates 12 and '13. Also preferably .an access opening 9, shown by dotted lines in vFig 1 and covered-by a removable plate 9 is providediin-the lower portion of at least one of the'upper side plates, suchas side plate 11.

Two bearing members 17 and 18, Fig. 5, are secured to the lower side-plates 12 and 13 respectively and a shaft 19 is rotatively supported in these bearing members. A 'sprocketwheel 20 is non-rotatively and fixedly secured on the shaft '19 and is positioned between the two lower side plates 12 and-13. Two discs 21 and 22 are keyed or otherwise non-rotatively secured on the shaft 19 outwardly from the bearing members 17 and 18 and two drums 23 and 24 are secured to the respective discs 21 and 22. Each drum23 and 24 has at least one digger member secured thereto. By way of illustration 1 have shown four digger members indicated generally by numerals 25, 26, 27 and 28 in Fig. 1, the two digger members 25 and 26 "being attached at diametrically opposite positions tothe drum 24 and two other digger members 27 and 28 being attached to the drum 23 at diametrically opposite-positions and at locations offset substantially ninety degrees relative to the digger members :25 and 26. The two digger members'on each drum 23 and 24 are also transversely offset relative to each otherso they will'not follow the same path. When the digger members on a drum are thus transversely offset they will followpathsalo-ngside of each other when thedrum is rotated and thus cover a wider space.

The digger members .25, 26, 27 and 28 are all of duplicate construction and this construction may-be varied without departing from the principle thereof. Each digger member herein shown comprises preferably three flat spring leaves 30, 31 and 32, disposed in overlapped relation as best shown in Fig. 4. The medialleafSl of each spring is longer than the other two leaves 30 and 32 and extendsthroughout the length of the spring. Said medial.leaf.31 has reversely curved end portions and is shaped somewhat like adetter 'S 'The innerdea'fBI) and,

3 outer leaf 32 each have one end portion cuwed to conform to the curvature of the adjacent part of the medial leaf and said two leaves 36 and 32 are of the same general shape and are long enough so that they overlap each other'for a substantial distance throughout the medial position of the S shaped medial leaf 31. Thus the part by a medial leaf 31 and the two overlapped end portions of the leaves 30 and 31 are rigidly secured to the drum as by a cap screw 34 which extends through the spring leaves and is threaded into the drum and a clamp bar 35 which extends across the spring leaves 30 and 31 and is secured to the drum by other cap screws 36. The overlapped outer end portions of each medial spring member 31 and outer spring member 32 have a fiat chisel shaped digger point or pick 37 secured thereto as by cap screws 38. The overlapped outer end portions of each pair of spring leaves are curved in the opposite or reverse direction from the inner end portions of said spring leaves and the drum to which the spring members are secured is rotatively driven in the direction of curvature of the outer end portions of the spring leaves when the digger is in use. The plane of each digger point 37 always coincides approximately with the arc of the circle in which it moves. The inner end portion of each spring member contacts its drum for a short distance at the location of the clamp member 35 and cap screws 34 and 36 and then begins to recede or spiral away from said drum. The medial portion of each spring member, that is the part thereof in which the three leaves overlap is approximately tangential to the drum. The inner end portion of each spring will tend to warp around its drum and thereby retract or move the digging point carried by said spring inwardly toward the drum if said digging point contacts an obstruction which substantially retards its movement in a circular path.

The sprocket wheel 20 on the drum carrying shaft 19 is driven by a sprocket chain 39 which extends upwardly and passes around a smaller sprocket wheel 40 on a shaft 41. The shaft 41 is journaled in bearings 42 which are supported on a horizontal platform 43 that is rigid with the upper end portion of the frame formed in part by the side plates and 11. Power to drive shaft 41 may be transmitted, from any suitable source, by a sprocket chain 44 operating on a sprocket Wheel 44'.

Suitable elevator means is provided for elevating and disposing of material loosened or dug up by the digging means. This elevating means, as herein illustrated, comprises two upright, spaced apart parallel frame bars 45 rigid with each other and rotatively supporting an upper transverse shaft 46 and a lower transverse shaft 47. The shafts 46 and 47 carry sprocket wheels 48 on which link belts 49 are operatively disposed. Buckets 50 of conventional type are carried by the link belts 49 and move in the direction indicated by the arrows in Fig. l. Preferably a backing plate 56 is provided just back of the link belts 49 at the side of the conveyor adjacent the digging unit. This plate 56 serves as a backing for the link belts 49 and as a baflle or stop for material thrown off by the adjacent digger. The link belts of the conveyor may be driven by a link belt 51 operating on a sprocket wheel 52 on shaft 46 and connected with any suitable source of power.

Preferably the lower conveyor supporting shaft'47 is mounted in links 47a which are connected by pivot 'and thence to any suitable hoisting means.

is secured to said drum 23.

members 47b with the upright frame bars 45 so that the buckets 50, in passing around the lower sprocket wheels 48, can raise upwardly if said buckets strike against rocks or other solid and non-yielding material in the bottom of a ditch or trench. Links 47a and pivots 4712 are in duplicate at the two sides of the conveyor.

As material is loosened by the spring mounted digger members 37 it falls or is pushed into the moving buckets 50 or is picked up by said buckets and is elevated and discharged into a transverse chute or conveyor 53.

The digger means and the elevator means are interconnected with each other by devices which will permit independent vertical adjustment of these two units. As illustrative of one way of providing this connection the drawings show the upright elevator frame bars 45 to be channel members with inwardly directed flanges forming tracks within which track rails 57, Fig. 2, are slidably disposed. Each track rail 57 is rigid with, preferably two, vertically spaced apart connector bars 58 and 59 which extend at right angles to the track 57 and are secured by bolts 60 to outwardly extending flanges 61 of other bars 62 and 63. The bars 62 and 63 are rigid with the digger frame formed in part by side plates 10 and 11.

The elevator unit may be supported from an overhead boom 64 by a cable 65 which passes over sheaves 66 Also the digging unit may be supported from the boom 64 by an independently operated cable 67 which is connected by other cables 67 with the digging unit. The cable 67 passes over sheaves 68 on the boom 64 and thence to suitable hoisting means, not shown. Preferably the boom 64 is supported from a tractor or like piece of equipment by which the ditching mechanism may be moved. A fragment of a mobile boom supporting device 69 is shown in Fig. l.

The upright bars 45 of the elevator frame are herein shown as being supported for vertical movement by channel shaped guide members 70 and horizontal bars 71 are illustrated as supporting the guide members 70 from the truck or tractor 69. Obviously the form of these supporting devices may be varied as long as they provide support for the upright bars 45 and elevator and digger means connected therewith.

The two digger members 26 and 27 which are positioned near the outer ends of the respective drums 24 and 23 are preferably inclined outwardly a slight amount so that these two digger members will dig a ditch which has a width slightly greater than the overall distance between the planes of the outer ends of the two drums and thus provide ample working clearance. This may be accomplished by inserting a wedge between the end portion of each outermost digger member and the drum to which it is secured. Fig. 7 shows such a wedge 55 provided between the drum 23 and the ends of the springs 39 and 31 of the digger member 27 which Preferably a V-shaped deflector 54 is secured to the digger frame 10, 11, 14. Figs. 1, 2 and 3, at a location coincident with the path of travel of the digger points 37 so that the digger points 37 which operate closest to the frame can not catch on the frame parts 10, 11 and 14.

The drums 23 and 24, shown in Figs. 1 to 5, each have two digger members secured thereto. If it is desired to use more than two digger members in connection with each drum or with either drum to dig a Wider ditch then an extension drum 72, Fig.. 6, can be secured to each of the drums 23 and 24 or to either of said drums, as by longer bolts 73, and the extension drum 72 can carry any desired number of digger members. If the extension drum 72 carries only one digger member then the position of attachment of one of the digger members on the main drum ,to which the extension drum is secured will preferably be changed to provide ,5 equal angular spacing between the threedigger members thus used.

The housingprovided .byparts to 14.inclusive is of narrow width and hasa diggingunit on each side thereof. The leaf spring digging members extend a substantial distance beyond the housing and it has been found that when the material on both sides of the housing is dug away the material in the plane of the housing will be jarred loose andwill usually crumble readily and fall to the bottom of thetrench either before it is contactedby the housingor when it is subjected to the pressure ofthe housing. This material will be pushed into the buckets-and picked-up-by the buckets.

In the use of this device to start a ditch the digging unit and elevator are both lowered onto the surface of the groundwhere the ditchisto be started. Operation of the digging unit will scoop out a hole in the ground to a substantial depth below the level of the elevator and deliver most of the scooped out material into the elevator buckets. The digging unit is then raised out of the hole thus dug, the machine is moved forward, the elevator is lowered into this hole and a second hole substantially deeper than the first is excavated and the displaced material disposed of. This procedure is repeated until the desired depth of ditch is reached, after which the elevator operates in the ditch, indicated by D in Fig. 1 and the digging unit works from the top down to successively excavate bites or sections of material in front of the elevator.

The leaf springs support the digger points resiliently and provide considerable flexibility in sidewise directions and these springs can be wrapped on the drums enough to provide substantial retractile movement toward the drums of the digger points 37. The drums are driven fast enough to impart considerable momentum to the relatively heavy digger points 37 but not fast enough so that centrifugal force has much influence on the action of the digger points. In soft clay and the like these points scrape and shave away the material. In solidified gravels the digger points strike just hard enough to shatter and chip away the material. If these points encounter a boulder they will either recoil, due to the wrapping of the leaf springs on the drums, or they will be deflected sidewise around the boulder, and in repeatedly doing this, will work around the boulder and drop it into the ditch or cavity.

The foregoing description and accompanying drawings disclose a preferred embodiment of my invention but it will be understood that changes in the same may be made within the scope of the following claims.

I claim:

1. In ditch digging apparatus, a rotatively driven drum; and a reversely curved flat metal leaf spring carried by said drum, said spring having an inner end portion curving around the drum and secured to the drum and a medial portion extending away from the drum and an outer end portion curved in a reverse direction from the inner end portion and terminating in a relatively heavy impact type chisel shaped digger point.

2. In ditch digging apparatus, a rotatively driven drum; a reversely curved fiat metal leaf spring carried by said drum, said spring having an inner end portion curving around the drum and secured to the drum and a medial portion extending away from the drum and an outer end portion curved in a reverse direction from the inner end portion; and a chisel shaped digger point of relatively heavy weight secured to the outer end portion of said spring and extending beyond the end of said spring.

3. In ditch digging appartus, a rotatively driven drum; and a plurality of relatively transversely offset reversely curved fiat metal leaf springs carried by said drum in equally spaced relation angularly of said drum, each of said springs having an inner end portion curving around the drum and fixedly secured to the drum and a medial portion extending away from the drum and an outer end portion curved in a reverse direction from the inner end portion. andterminating in a relativelyheavy impact type chisel shaped digger point.

4. The apparatus. as claimed in claim 3in which at least one leaf springispositioned near an endof the drum. and

is slightly inclined outwardly relative to a plane flush with said-end'of thedrum and perpendicular to the axis -of-the drum, .whereby-the digger point on the outer end -of., said spring will overhang the adjacent end of the drum respective sides thereof; anda plurality of relatively transversely offset flat metal leafsprings of approximately '3 shape carried by each ofsaid drums, each of said springs havingan inner.end,portioncurving around a drum and fixedly secured to the drum and a medial portion extending away from the drum and an outer end portion curved in a reverse direction from the inner end portion and terminating in a relatively heavy impact type chisel shaped digger point.

6. In ditch digging apparatus, a thin flat hollow upright digger frame; a shaft extending crosswise of the lower end portion of said frame; bearings rigid with the frame rotatively supporting the shaft; driving means connected with the shaft and operating within the frame; two drums fixedly mounted on said shaft adjacent the respective sides of said frame; at least one substantially S shaped multiple leaf spring digger arm carried by each drum and extending outwardly from the drum in a plane substantially at right angles to the axis of the drum, each spring having a curved inner end portion extending partially around the drum and secured to the drum; and a relatively heavy impact type chisel shaped digger point of substantial weight secured to the outer end portion of each of said springs and overhanging the adjacent end of the spring.

7. In ditch digging apparatus, a thin flat upright hollow digger frame; a shaft extending crosswise of the lower end portion of said frame; bearings rigid with said frame rotatively supporting said shaft; a sprocket wheel disposed within said frame and secured to said shaft; a driven link belt within said frame driving said sprocket wheel; two drums rigidly mounted on said shaft adjacent the respective sides of said frame; a plurality of relatively transversely offset reversely curved flat metal leaf springs carried by said drum in angularly spaced relation on the drum, each leaf spring having an inner end portion curving around a drum and secured to the drum and a medial portion extending away from the drum and an outer end portion curved in a reverse direction from the inner end portion thereof; and a chisel shaped digger point of substantial weight and of a width at least equal to the width of the spring secured to the outer end portion of each spring and extending beyond the end of the spring, the plane of each digger point coinciding substantially with its arc of movement for all positions of the digger point and each digger point and the adjacent part of its spring cooperating to discharge material forwardly away from the digging apparatus.

8. In ditch digging apparatus, a rotatively driven drum; and at least one reversely curved substantially S shaped multiple leaf spring having its inner end portion extending partially around the drum and secured to the drum and having its remaining portion extending outwardly from the drum, said spring comprising a flat metal medial leaf extending throughout the length of the spring, an inner leaf fitting within the concave inner end portion of the medial leaf and extending to a point near the curved outer end of said medial leaf, and an outer leaf fitting within the concave outer end portion of the medial leaf and extending to a point near the concave inner end portion of the medial leaf, said inner and outer leaves overlapping for a substantial distance, spring clamps securing the three spring leaves together adjacent the respective ends of the inner and outer leaves; and an impact type relatively heavy flat chisel shaped digger point of a width at least equal to the width of the spring leaves rigid with and extending beyond the outer end portions of the spring leaves, said digger point in operation providing impact for loosening solid material.

9. In ditch digging apparatus, a rotatively driven drum; a reversely curved flat metal leaf spring carried by said drums, said spring having an inner end part contacting said drum and secured to the drum and an adjacent inner portion curved around the drum and receding away from the drum outwardly considered and having a medial portion extending away from the drum and an outer end portion curved in a reverse direction from the inner curved portion; an impact type relatively heavy flat chisel shaped digger point of a Width at least equal to the width of the spring secured to and extending beyond the outer end ofv the spring; and means driving the drum in the direction of curvature of the outer end portion of said reversely curved leaf spring, whereby when the outer end portion of said spring is restrained from movement in a circular path said spring will be drawn around said driven drum and the digger point will be moved toward said drum.

References (Iited in the file of this patent UNITED STATES PATENTS Re. 17,837 Bullock Oct. 21, 1930 1,840,188 Dufour Jan. 5, 1932 2,020,524 Smithburn Nov. 12, 1935 2,549,088 Hettelsater et al. Apr. 17, 1951 2,683,406 Kelsey July 13, 1954 FOREIGN PATENTS 370,694 Germany July 23, 1921 

